[PATCH 6.1 0845/1191] perf intel-pt: Fix off-by-one in auxtrace_info minimum size check

From
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date
2026-09-12 16:31:23
Also in
linux-patches
Reply to
Greg Kroah-Hartman, 2026-09-12
6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Arnaldo Carvalho de Melo <redacted>

[ Upstream commit c4362d5e1a5ed4ce2098798f655a636c4340fa20 ]

min_sz is set to sizeof(u64) * INTEL_PT_PER_CPU_MMAPS, but the code
accesses auxtrace_info->priv[INTEL_PT_PER_CPU_MMAPS], which requires
at least INTEL_PT_PER_CPU_MMAPS + 1 elements.  A file with exactly
min_sz bytes of priv data passes the size check but the access reads
one u64 past the validated region.

Use (INTEL_PT_PER_CPU_MMAPS + 1) to ensure the highest accessed index
is within bounds.

Fixes: 90e457f7be087005 ("perf tools: Add Intel PT support")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <redacted>
Reviewed-by: James Clark <james.clark@linaro.org>
Reviewed-by: Adrian Hunter <adrian.hunter@intel.com>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/perf/util/intel-pt.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/intel-pt.c b/tools/perf/util/intel-pt.c
index 018eaddd4e6af..3a1dd70ccd2f9 100644
--- a/tools/perf/util/intel-pt.c
+++ b/tools/perf/util/intel-pt.c
@@ -4290,7 +4290,7 @@ int intel_pt_process_auxtrace_info(union perf_event *event,
 				   struct perf_session *session)
 {
 	struct perf_record_auxtrace_info *auxtrace_info = &event->auxtrace_info;
-	size_t min_sz = sizeof(u64) * INTEL_PT_PER_CPU_MMAPS;
+	size_t min_sz = sizeof(u64) * (INTEL_PT_PER_CPU_MMAPS + 1);
 	struct intel_pt *pt;
 	void *info_end;
 	__u64 *info;
-- 
2.53.0


Thread (1,211 messages) 1,211 messages, 13 authors, last reply 2026-09-21
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